Plate valve

A plate valve comprising:

• valve seat means, said seat means having a flat seating surface and a first plurality of circumferentially arranged ports of arcuate shape spaced apart radially about an axis of the valve, said ports intersecting said seating surface and providing fluid communication between said seating surface and an oppositely disposed side of said seat means;
• guard means, said guard means having a second plurality of circumferentially arranged ports of arcuate shape spaced apart radially about said valve axis, the ports of the second plurality being radially offset with respect to ports of said first plurality and extending between a pair of oppositely disposed sides of said guard means, said seat means and said guard means cooperating to define a valve chamber therebetween, the seating surface being disposed in said chamber;
• means for securing said seat means to said guard means;
• a plurality of concentric annular valve plates in said chamber, said valve plates being spaced apart radially about said valve axis and being aligned with the ports of said first plurality, said plates having a thickness which exceeds 0.2 inches and having a thickness to width ratio which exceeds 0.5;
• and
• means for resiliently biasing said plates towards said seating surface, said biasing means including a plurality of springs cooperating with each of said plates, the ratio of the number of springs associated with each plate to the mean diameter of that plate being greater than 1.2 per inch.